Studio Flash With 20D and E-TTL Metering

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Hi.all.

If you are using studio lights that are triggered by slave units, does this
mean that the flashes will be triggered too soon with the 20D?

The reason I ask is because with the E-TTL metering, the camera sends out
two flashes, one for the metering, and a second one straight afterwards for
the actual photo. Does this mean that the first 'metering flash' will
trigger the flash units? If so, is there a way round it?

Archived from groups: rec.photo.digital (More info?)

"Russell" <nospam@nospam.com> wrote in
news:_6KdnfaqKroB4hLfRVnyjg@pipex.net:

> If you are using studio lights that are triggered by slave units, does
> this mean that the flashes will be triggered too soon with the 20D?

PC port = no preflash.

If you are attempting to trigger optical slaves from a Canon speedlight,
you will have to pony up the extra bucks for units such as the Weins that
ignore the preflash. Truthfully, that is a pretty pricey and hardheaded way
to operate.

Archived from groups: rec.photo.digital (More info?)

"Bill Hilton" <bhilton665@aol.com> wrote in message
news:1116705516.493753.31980@g44g2000cwa.googlegroups.com...
>> The reason I ask is because with the E-TTL metering, the camera
>>sends out two flashes ...
>
> You should probably turn off E-TTL since you're not using it with these
> external lights ... I think this disables the pre-flash on the Canon
> flashes.
>
>>Does this mean that the first 'metering flash' will
>>trigger the flash units? If so, is there a way round it?
>
> Another way to trigger the studio flashes (if you don't want to use a
> PC cord) is to just buy a cheap small Vivitar or similar flash and use
> it as the trigger. This also by-passes E-TTL since those flashes don't
> support it. I think the one I use costs around $20 or so.
>

Hi.

Just to make it clear to the OP, you mean put the little flashgun onto the
Hot Shoe, and set the camera to manual exposure mode. Also make sure the
flash does not give out sufficient light to affect the exposure, just enugh
to activate the slave sensors. If you do not want it to produce a Catch
Light, a little piece of kitchen foil can be used to deflect its light
upwards to the ceiling.

I use a very small flash GN 12 ft @ 100ASA. It is so small it seems to run
forever on 1 AA.

Roy G